Research Of Calculation And Simulation Analysis About The Whole High Speed Engine’s Vibration

Under the background of lightweight and lower noise of engine, this thesis buildsthe digital model of a type of high speed gasoline engine by Pro/Engineer software,including cylinder head, cylinder block, cylinder bottom, oil pan and crankshaft, dealswith the FEM using the HyperMesh, calculates the modal parameter of the maincase-system and the whole engine combined with the modal analysis.combing with the FEM theory and multi-dynamics, we keep a certain number ofthe freedoms of the FE model by static condensation. After doing condensation, weobtain some information of the whole FEM geometry and the structure of the enginewhich contains the main nodes and freedoms, the Mass Matrix, Stiff Matrix andDamping Matrix. The information is imported into the multi-dynamics of whole en-gine model as the geometry data sources.We deal with the analysis of the structure vibration of the whole engine using theFEM theory and the multi-dynamics. By using Timing Drive and Power Unit which isinstalled in AVL Excite software, we carry out the multi-parameters input as externalcondition and couple the calculations of the valve timing mechanism and connectingrod system. In order to discuss the vibration response status of the whole engine underthe internal and external load, we should add the inner load which includes the outputtorque and gas explosion pressure, and external load which contains the piston slapforce and valve exciting force into the multi-dynamic model, check out the main ex-citing force which cause the huge displacement vibration of engine structure usingcolor map and special regions in engine skin face.We can conclude the whole engine skin vibration velocity through data recoveryafter the simulation and calculation. We redesign the structure of engine under theguidance of the Design Optimization Methods. Through designing the structure in thekey part to enhance the stiffness of the engine case-system, we can attain the goal ofreducing the engine skin vibration velocity and noise radiation.